The present invention relates to the field of mechanical systems and methods and more particularly, to mechanical actuators and methods.
Bimorph microactuators are discussed, for example, in the reference by M. Edward Motamedi et al. entitled Development Of Micro-Electro-Mechanical Optical Scanner. (Opt. Eng. 36(5) 1346-1353, May 1997.) In particular, bimorph microactuators are micromachined beams whose curvatures can be controlled by applying electrical signals. The simplest bimorph actuator is a composite beam with different structural and electrical properties in its individual layers. The behavior of a bimorph actuator can depend on the dimensions, densities, elastic coefficients, thermal expansion coefficients, and/or piezoelectric properties of the individual layers making up the beam.
The use of a bimorph actuator beam in a monolithic silicon integrated optical micro-scanner is discussed in the reference by S. Calmes et al. entitled Resonating Large Angle And Low Consumption Micromachined Optical Scanner. (SPIE Vol. 3276, pp. 96-102, 1998.) In this reference, the device includes a mirror located on the tip of a thermal bimorph actuator beam. The device is excited electrothermomechanically at its resonance frequency, enabling large angular deflections at low power consumption. Additional bimorph actuator structures are discussed in the reference by Xi-Qing Sun et al. entitled A Bistable Microrelay Based On Two-Segment Multimorph Cantilever Actuators (Proceedings of the IEEE Micro Electro Mechanical Systems, 1998, pp. 154-159). The disclosures of each of the Motamedi et al., Calmes et al., and Sun et al. references are hereby incorporated herein in their entirety by reference.
Notwithstanding the bimorph actuators discussed above, there continues to exist a need in the art for improved actuators and methods of forming the same.